On-demand neutralization of acid-preserved food

ABSTRACT

The invention relates to a food composition having an increased shelf stability and robustness when stored in microbiologically sensitive conditions which comprises an acidifying preservative system adapted to reduce the microbial growth in the composition and a neutralizing system which is inactivated in said microbiologically sensitive conditions and is adapted to activate on demand upon reactivating conditions of the neutralizing system are met so that the neutralizing system acts on the acidifying preservative system to neutralize its sourness and/or acidity thereby improving the taste perception of the composition. The invention also relates to a dry blend usable as a preservative system in food, particularly deferred cooking food that requires storage in microbiologically sensitive conditions.

TECHNICAL FIELD

[0001] The present invention relates to a food composition adapted toproduce a food product that has an enhanced robustness tomicrobiological spoilage and a reduced sourness. The invention alsorelates to a method for providing in a convenient manner amicrobiologically robust food product of reduced sourness from such afood composition. The method also relates to a preservative blend thatcan be added to food, in particular to deferred cooking food, for thepurpose of increasing its shelf life and improving its robustnesswithout negatively affecting flavor or taste.

BACKGROUND OF THE INVENTION

[0002] Growing popularity for good tasting and convenient food productshas increased in recent years. In food service areas or in foodmanufacturing plants, it is usual to prepare relatively large amounts offood products to consume at a later time. This is especially true ofproducts derived from dehydrated forms. Food products such as naturallylow acid products can quickly form a favorable medium and promotesuitable conditions for rapid microbial growth as soon as they becomehydrated, and this presents handling concerns.

[0003] Low acid food products need absolutely to be stored inrefrigerated cabinets at a temperature that should not exceed 8° C. Suchstorage will inhibit the growth of bacteria, yeast and molds in the foodproduct. Microbial growth also depends on the degree of contamination inthe product during its preparation. Although measures can be taken tolimit cross-contamination in manufacturing plants, it may be moredifficult to ensure proper hygiene and handling in foodservicepreparation kitchens. For example, it is known that food products mayendure abuse temperature conditions (i.e., temperatures of 10° C. orhigher) in these areas. Such conditions may occur when the refrigerationcabinet does not perform very well or when the cabinet is left open toooften and/or too long.

[0004] Low-pH vegetable-based meals such as mashed potatoes are knownfor being very microbiologically sensitive products that become spoiledvery quickly. To prevent microbial development, these products may bepreserved under acidic conditions wherein the pH is maintainedsufficiently low to suppress growth of pathogenic and spoilage bacteria.To be effective, the pH of the product needs to be maintained at valuesof less than 4.6 by adding an acidic preservative system of weak organicacids such as acetic acid or citric acid and/or acetates such as sodiumacetate and other similar compounds.

[0005] Attempts to solve the problem of storage of low acid foods hasbeen described in U.S. Pat. No. 4,145,451 to Oles, whereinmicrobiological spoilage is prevented by use of phosphoric acid insynergistic combination with acetic acid, and in absence of the usualchemical food preservatives.

[0006] U.S. Pat. No. 4,756,919 discloses a method of preserving foodproducts against microbiological spoilage by adding thereto forpreservation purpose fumaric acid or fumaric acid in combination with afood acidulent at a level sufficient to prevent spoilage.

[0007] After the food product has been treated with an acidicpreservative system, however, it receives much lower acceptance from theconsumer as compared to a food product that has not been treated at all.The problem of acceptance comes from the sourness and/or acidity of theproduct that adversely effect its original taste and organolepticproperties. The acidity may also cause other problems such as digestiveor gastric issues. Thus, there is a need for increasing the shelf lifeof food products while preserving the taste perception and organolepticproperties of such products, and the present invention satisfies thisneed.

SUMMARY OF THE INVENTION

[0008] The present invention provides a solution to the problems of theart, more particularly in the use of its findings that the robustnessand shelf life of a food product can be successfully improved while theorganoleptic and taste properties of the product are properly restoredat the time the product is ready for consumption.

[0009] The present invention thus benefits both the efficiency of theuse of preservative in low acid food products and the maintainance ofthe organoleptic properties of food products, in particular, even, ifnon-exclusively, in naturally low acid food products. Consequently, theinvention improves the quality and characteristics of food products thatare acidified to endure a period of storage in microbiologicallysensitive conditions without significant spoilage.

[0010] Also, the invention increases the shelf stability and robustnessof food products that contain an acidic preservative system whilereducing the sourness and/or acidity of the food product upon demandand/or before serving.

[0011] Furthermore, the present invention enables the storage ofmicrobiologically sensitive food product in a cold or chilledenvironment for an extended period of time while not significantlyaffecting the organoleptic qualities of the food product at the timethat the product is delivered to the consumer.

[0012] The invention also increases the shelf life of food products,more particularly of food products that are stored chilled for deferredcooking, without negatively affecting flavor and taste perception ofsuch products.

[0013] Finally, the present invention increases convenience in theservice of food products to consumers, in particular in the foodservicearea, by allowing microbiologically sensitive food products to beprepared in advance and safely stored in wet and chilled environmentwhile still providing a high quality, good tasting food product at thetime of serving.

[0014] In its product aspect, the present invention relates to a foodcomposition comprising an acidifying preservative system adapted toreduce the microbial growth in the composition. The preservative systemis preferably effective when the composition is stored inmicrobiologically sensitive conditions. The composition further includesa neutralizing system adapted to neutralize the effect of the acidifyingpreservative system. Importantly, the neutralizing system is maintainedsubstantially inactive at the time the food composition is in themicrobiologically sensitive conditions of storage. The neutralizingsystem is preferably adapted to activate on demand, i.e., whenreactivating conditions are met, so that the neutralizing system acts onthe acidifying preservative system to neutralize its acidity therebyreducing the sourness and/or acidic taste and, consequently, improvingor, at least restoring, the organoleptic perception of the food.

[0015] Conditions that are sensitive to the microbial growth for thefood composition would be considered such when the food compositionbecomes sufficiently hydrated. The composition may become hydrated byaddition of water, if the food component itself is dehydrated or, by thenature of the food component itself, if for instance, the food componentis a fresh food such as fresh vegetables and the like.

[0016] In addition, conditions that are sensitive to the microbialgrowth further include temperature conditions which do not completelystop the growth of bacteria, yeast and molds and/or degradation of food.Those temperature conditions may be chilled conditions, abuse conditionsor ambient temperature conditions.

[0017] The neutralizing system is preferably reactivable on demand suchas by heating of the food composition. Heating may be carried out eitheron the sole purpose of reactivating the neutralizing system or on thecombined purpose of reactivating the neutralizing system and serving thefood composition hot or warm. In the first alternative, the foodcomposition may be subsequently cooled down and served at a lowtemperature or cold temperature if, for instance, it fits the usual wayof serving the food. In all cases, the neutralizing effect shouldpreferably take place during the heating phase or, at least, at thefinal stage of the heating.

[0018] In a preferred aspect of the invention, the neutralizing systemis encapsulated to substantially resist, or at least delay, the fullrelease of the neutralizing effect when the composition is maintained inmicrobiologically sensitive conditions of storage. By “substantiallyresistance to release”, it is meant that a certain level of release ofthe neutralizing system may be accepted over a period of from about 1 to7 and preferably from 2 to 5 days, even if not preferred, provided theacidifying preservative system still remains effective enough inreducing the microbial spoilage.

[0019] The invention also relates to a dry blend of an acidifyingpreservative system adapted to prevent or, at least reduce, themicrobial growth in a food when the food is stored in microbiologicallysensitive conditions and a neutralizing system. In this embodiment, theneutralizing system is encapsulated to substantially delay release inthe microbiologically sensitive conditions and is adapted to fullyrelease upon heating of the neutralizing system so that the neutralizingsystem acts on the acidifying preservative system to neutralize itssourness and/or acidity thereby improving the taste perception of thefood.

[0020] In its process aspect, the present invention is directed to amethod for increasing shelf stability of a microbiologically sensitivefood composition under standard storage temperature conditions androbustness of the composition under abuse temperature conditions byadding an acidifying preservative system in sufficient amounts topreserve the food against microbial spoilage, and an on-demandreactivable neutralizing system to decrease the sourness and/or acidityof the food composition when reactivated.

[0021] In a more specific and focused aspect, the method of theinvention may preferably be used for providing to a foodservice,manufacturing or selling location an hydratable food composition ofimproved microbiological robustness, when it is in hydrated form. Thus,the method comprises providing a dehydrated food composition including adry food component, a preservative system effective to reduce themicrobiological growth in refrigerated and abuse conditions, aneutralizing system that is essentially activable on demand.

[0022] In a preferred aspect of this method, the neutralizing agent isactivable by raising the temperature of the composition to a temperaturerange higher than the temperature range of the microbial sensitivestorage conditions and sufficient to activate the neutralizing system.

[0023] The invention also relates to the use of a combination of anacidifying preservative system and a neutralizing system in a foodcomposition to improve the taste perception or organoleptic propertiesof the product. Again, the acidifying preservative system is used in anamount effective for preventing or at least reducing the microbialgrowth in the food composition while the neutralizing system isinactivated in microbiologically sensitive conditions of storage of thefood composition but is adapted to activate on demand to act on theacidifying preservative system to neutralize its sourness and/or aciditythereby improving the taste perception or organoleptic properties of thefood composition.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] The present invention relates to a food composition that hasenhanced properties of robustness and an extended shelf stabilityobtained by the use of an acidic preservative system in amountseffective enough for the intended purpose and that further hasproperties to neutralize the sourness and/or acidity of the preservativesystem by the use of a neutralizing system that acts on demand on theacidic preservative system to at least partially neutralize thepreservative system and, consequently, improve the organolepticproperties and perception of taste of the food.

[0025] The term “robustness” as used herein refers to the ability of thefood composition to offer an effective antimicrobial effect when thecompositon is submitted to abuse conditions of storage.

[0026] The term “abuse conditions” used herein refers to conditions oftemperature that usually exceed the recommended conditions of storagefor the intended food product. In particular, it is recommended tomaintain low acid food products such as mixed or mashed products at arefrigerated temperature just above the freezing point, between 1 to 8°C., preferably at 4 and 7° C., in the US and UK, respectively, duringstorage of the wet product.

[0027] The term “extended shelf stability” used herein refers to therelative ability to increase the life time of the composition whenstored under the microbiologically sensitive conditions of storage ascompared to a composition with no acidic preservatives.

[0028] The term “microbiological spoilage”, as used herein, relates tothe spoilage that is caused by growth of yeast, mold and/or bacteriaincluding lactobacilli.

[0029] The Preservative System:

[0030] The use of acidic preservatives in the present invention isessential to maintain low pH conditions in the food medium so that nosignificant spoilage may occur during the storage period of the food.The types, amounts and relative proportions of the acidic preservativesmay greatly depend on the nature of food, temperature conditions andpackaging conditions. As low pH conditions, it is referred to pH valuesof 5 or lower, more preferably to pH of from 3 to 5. At these effectivevalues of pH, panel tests have shown that the taste appears relativelysour and usual food such as naturally low acid foods are stronglyaffected by the sourness and acidity coming from the preservativesthereby reducing the consumer's acceptance of the product.

[0031] The preservative system may preferably comprise an acidulentconsisting of at least one organic acid effective for its antimicrobialeffect in food. Unsaturated organic carboxylic acids are known for theirincreased antimicrobial effect as compared to saturated acids and arepreferred for that reason.

[0032] The acidulent may be chosen among the group consisting of citricacid, ascorbic acid, sorbic acid, tartaric acid, cream of tarter,fumaric acid, lactic acid, malic acid, acetic and combinations thereof.In a preferred embodiment, the acidulent is citric acid in powder formthat is to be dry blended into the product. The use of a dry acid is tomaintain the product in a fully dehydrated form for extended periodsuntil ready for use. Suitable levels of organic acid, and preferablywhen citric acid is used, range from about 0.05 to 5 wt %, or morepreferably about 0.1 to 0.2 wt % of the total dry food composition.

[0033] The preservative system may preferably comprise at least onepreservative agent in addition to the acidulent that acts with theacidulent to offer an enhanced antimicrobial effect within the foodmedium. A preservative agent in the context of the invention maypreferably comprise one or more salt(s) of weak organic acid(s) that has(have) the ability to completely dissociate in aqueous solution. Whencombined in an acidic environment, the salt of organic acid will form alevel of undissociated molecules which are antimicrobial in nature. Thesalts of organic acids have the disadvantage to increase the sourness ofthe food product in concentration effective for the intendedanti-spoilage effect of the perishable food. Salts of organic acids thatare generally useful in the product and method of the invention includealkai metal citrates, benzoates, gluconates, sorbates and the like.These are advantageously utilized in a dry crystal form. Preferably,sodium acetate, monosodium citrate, trisodium citrate, potassiumbenzoate, sodium benzoate, potassium citrate, potassium gluconate,potassium sorbate, and combinations thereof can be used. Those salts areavailable in a crystal form that can be added in the required amounts tothe food product. As the food product becomes hydrated, the crystalstend to dissolve in the food product in an homogeneous manner. In a morepreferred embodiment, acetate, preferably sodium acetate, is used.Suitable levels of these salts range from about 0.05 to 5 % wt, and morepreferably, form about 0.1 to 2 % wt. of the dry composition.

[0034] It has been found advantageous that the acidulent and salt-basedpreservative agent be used in combination in a ratio of from 1:1 to 5:1,preferably of from 2:1 to 4:1 (wt/wt) so that the antimicrobial effectis maximized.

[0035] When the food product is a dehydrated food product that has to bereconstituted in an aqueous medium, the total amount of the preservativesystem should be controlled depending on the dilution ratio of the dryfood product in water to provide the effective antimicrobial effect. Inparticular, the preservative system form should preferably represent intotal about 0.01 to 1 % wt, even more preferably about 0.1 to 0.5 % wt,of the reconstituted moisturized food composition.

[0036] The invention could be configured that would not include thepreservative agent (e.g., sodium acetate), but the preservative systemwould presumably be not as efficient as when the preservative agent isincluded.

[0037] The Food Product:

[0038] The food product of the invention may be a solid, liquid,pourable, semi-solid, emulsified or non-emulsified, food product. Thefood product may include, but not limited to vegetables, salad,porridge, soup, sauce, fish, meat, beverage, dressing, cream, a bakedproduct, dough and combinations thereof. The food product may preferablybe stored under a form that favors preservation under long term storageat ambient. For instance, the food product may be a dry or liquidconcentrated food product.

[0039] When in dry form, the food product should have the ability toreconstitute with water or any similar aqueous medium such as milk or anemulsion such as salad dressing and the like. Dry food products arethose obtained by dessication, freeze-drying, spray drying or otherdrying methods usually used in food technology. Dry food product mayform flakes, granules, powder, particulates, pieces and combinationsthereof. In the dry form, the food product may be kept several months ina packaging that performs against rancidity. The product may be packagedin sealed flow packs such as in aluminized plastic laminates in normalor eventually modified low oxygen atmosphere. At the time the product isprepared, the dry composition is combined with a recommended amount ofwater, in a container, with optionally additional ingredients such asshortenings, milk, salt, and optionally spices and the composition isstirred until to obtain a proper desired texture. The preparation isplaced in a chilled cabinet until it is time for serving it.

[0040] In its initial stage, the food product may also already bepartially or fully moisturized. When partially moisturized, the foodproduct may be a liquid concentrate of relatively low water activity;e.g., less than 0.8 so that the food product may be kept stored forseveral months at ambient temperature storage conditions. The partiallyor fully hydrated products may advantageously be packaged in pouches,bottles or packs. The product can be stored under aseptic conditions.For instance, the product may be filled aseptically and/or its packagingmay be flushed with a low oxygen gas such as N₂, CO₂ or combination.

[0041] Importantly, the food product is intended to form a wet foodproduct that becomes sensitive to ambient when water is added to it in apreparation stage. The preparation stage may be carried out in variousconfigurations such as in the course of the preparation of a complexmeal. For instance, the preparation stage may be carried out in amanufacturing plant or in a foodservice place. As soon as the foodproduct receives mositure or water and becomes wet, the food product isusually stored in a chilled cabinet; i.e., at temperature below 10° C.,so that microbial growth is significantly slowed.

[0042] The food product may also be manufactured from fresh foodingredients that are packaged in a suitable package such as in plasticor aluminum lidded trays under modified atmosphere and directly storedunder chilled temperatures.

[0043] The On-Demand Neutralizing System:

[0044] According to one essential aspect, the food composition furthercomprises a neutralizing system that is adapted to act on thepreservative system only on demand. The neutralizing system is resistantto activation in the conditions of storage including the wet conditionsin a chilled environment. The neutralizing system may preferably beactivated by heating the composition. The heating may correspond to thelatest stage of the preparation of the meal that contains the foodproduct. In an alternative, the heating stage may be an intermediatestage that is requested to suppress the sourness and/or acidity of thefood, and the food may be cooled down or frozen before serving it, ifrequired.

[0045] The amount of the neutralizing system in play directly depends onthe amount of the preservative system in the food composition so thatthe neutralizating effect can take place without providing an aftertasteeither alkaline or acidic. The active neutralizing agent in theneutralizing system should have GRAS (Generally Regarded As Safe)status, should be water soluble, should evenly distribute upon heatingand should not impart undesirable attributes to the food product.

[0046] In a preferred aspect of the invention, the neutralizing systemis rendered heat-activable by encapsulating the active neutralizingagent with an edible material that sufficiently resists leakage duringthe short-term storage in the sensitive conditions. Resistance toleakage should be of at least 2 days, preferably of 3 to 4 days, whenthe product is maintained under wet and chilled conditions. Theencapsulating material should preferably resists melting at temperatureof less than 50° C., more preferably less than 35° C., so that anypremature accidental release of the neutralizing agent can besuccessfully avoided such as when the outside temperatures of transport,storage, etc. are relatively elevated. The encapsulating material maypreferably be composed of fat materials from hydrogenated or partiallyhydrogenated vegetable oil, animal fat, combination or their derivation.The choice of fat is mainly dictated by its ability to resistdegradation or solubilization in a wet non-heated environment and itsability to melt or degrade in a heated environment. Therefore,hydrocolloid-based coating should be avoided as the presence of moisturein the food would normally cause the coating to solubilize therebycreating leakage of the active neutralizing agent. The encapsulatingmaterial should typically be composed of a lipid or lipid mixture havinga melting point adapted to the final nature of the product. Forinstance, if the food product is intended to be heated at hightemperature such as for mashed potatoes or orther hot meals, the fatshould preferably be chosen among oils or fat having a high meltingpoint such as cottonseed oil (melting point of about 63° C.), soybeanoil (m.p. about 70° C.) or palm oil (m.p. about 54 ° C.). To thecontrary, if the product is intended to be submitted to a warmtemperature stage such as a process of natural fermentation, e.g., doughproofing, the fat will be chosen among the low melting point solid fatsuch as high laurate canola oil (m.p. about 38° C.) and the like.

[0047] The encapsulation may be obtained by various known methods suchas by fluid bed coating, spray drying, spray chilling, spinning disk,tumbling or coacervation. In fluid bed coating, the first step consistsin melting the oil or fat as it is a hard fat at room temperature.Concurrently, the neutralizing agent is introduced into a fluidized bedreactor for the encapsulation process. The air flow passing through thereactor is adjusted so that the particles are slightly levitated. Theliquidized and free flowing oil is then sprayed over the active agent inthe fluidized bed reactor, thereby encapsulating it. The fluid airlevitating the agent is cooled, hereby causing the fat to solidify andencapsulate the agent. After the desired amount of coating is applied,the encapsulated agent is then removed from the fluidized bed reactor.

[0048] The neutralizing system is preferably formed from encapsulatedfood grade alkaline pH raiser such as phosphate that can be used incrystal or powder form. Crystallized phosphate is highly soluble inwater when it is not encapsulated. The encapsulation should sufficientlydiminish or delay the propensity of the phosphate crystals to solubilizein the moisturized food.

[0049] Phosphates useful in the present invention include mono-sodiumphosphate, di-sodium phosphate, tri-sodium phosphate, sodiumbicarbonate, calcium phosphates and combinations thereof. This mayinclude other materials that do not contain phosphates such as sodiumhydroxide, calcium oxide and calcium hydroxide. Very positive resultshave been found when using trisodium phosphate at 30% activityencapsulated in vegetable oil. As previously mentionned, the amount ofneutralizing system should depend on the overall preservative amounts.The amount of alkaline pH raiser directly depends on the amount ofpreservative agents to be neutralized. It has been found preferable tohave an amount of alkaline pH raiser of from about 0.05 to 8 % wt of thedry composition including the food part. If a dry blend is prepared withthe acidifying system and neutralizing system together intended foraddition to a food such as a commercial food, the ratio acidifyingsystem: neutralizing system should preferably be of from about 1:1 to1:10, preferably, 1:1.5 to 1:3. When using phosphate, it has been foundthat effective amounts of phosphate, preferably sodium phosphate, arewithin the range of from about 1 to 6 % wt of the dry composition and offrom about 0.05 to 2 % wt, even more preferably about 0.1 to 1 % wt, ofthe fully hydrated composition.

[0050] More particularly, the following relative proportions of theacidulent, the preservative agent and the alkaline pH raiser arepreferred for respectively dry or concentrate and fully reconstitutedcompositions (in % by weight):

[0051] 1. Dry or partially moiturized composition to be reconstitutedwith water at a dilution ratio of 1:1 to 1:10:

[0052] Food product: between 90 to 99%;

[0053] Citric acid: between 0.1 to 2%;

[0054] Sodium acetate: between 0.1 to 2%

[0055] Encapsulated trisodium phosphate: between 1 to 6%.

[0056] 2. Fully hydrated composition:

[0057] Food product: between 10 to 20%;

[0058] Citric acid: between 0.1 to 1%;

[0059] Sodium acetate: between 0.05 to 1%;

[0060] Encapsulated trisodium phosphate: between 0.1 to 1%;

[0061] Water: between 50 to 99%.

[0062] As aforementioned, the food composition of the invention mayinclude both the preservative system and the neutralizing system, asdescribed above, during the manufacturing stage. It is also possible toenvision that the neutralizing system be included at a later or deferredstage; i.e., at the time the food product is prepared and stored at themicrobiologically sensitive conditions; e.g., just before being keptchilled in a refrigerator or cold room. In that particular case, theacidified composition without the neutralizing system and theneutralizing system itself may be packaged separately. One benefit couldbe to prevent the degradation or deterioration of one component byanother. For instance, the encapsulation of the neutralizing system maybe prevented from degradation or deterioration that could be generatedby chemical and/or physical effects in the package with ingredients ofthe composition such as by oxidation, Maillard reaction, acceleratedrancidity, etc.

[0063] Dry Preservative Blend for Deferred Cooking Food Product:

[0064] The invention also encompasses a dry preservative blend that canbe used by addition to food, such as commercially available food thatrequires to be stored in microbiologically sensitive conditions anddeferred cooking and/or serving. The dry preservative blend comprisesthe acidifying preservative system adapted to prevent or at least reducethe microbial growth in the food and a neutralizing system that isencapsulated to substantially delay the release in the microbiologicallysensitive conditions and is adapted to fully release upon heating of theneutralizing system. The blend may be packed in any suitable closedcontainer or sachet adapted for extensive storage of dry substances. Theblend is added to the food and thoroughly mixed to the food to form anacid preserved food composition that is capable of withstanding severaldays in the compartment of a refrigerator or a cold room withoutsignificant spoilage. Once, the food is served, the food is heated to atemperature sufficient to fuse the fat based encapsulation and releasethe neutralization agent in the food thereby restoring a pH close to itsoriginal pH and a normal taste without sourness.

[0065] The present invention also encompasses a method for providing toa foodservice, manufacturing or selling location of a hydrated foodcomposition of improved microbiological robustness. The method maycomprise in one or more steps: providing a food composition including adry food component, providing a preservative system effective tomaintain microbiological safety in refrigerated and abuse conditions,and providing a neutralizing system that is essentially activable whenthe food composition is substantially heated. The method may beapplicable in food manufacturing plants or in the preparation of food infood distribution channels such as in restaurants, hospitals,convalescent houses, airline catering, supermarkets, convenient stores,etc. In particular, the method is ideal for deferred cooking and vendingapplications to provide further protection during cold storage. Inairline catering, for instance, the food composition can be prepared inadvance on the ground and stored in chilled carts in the aircraft untilthe product is ready for being rethermalized just before serving to thepassagers. The preservative system maintains the food productmicrobiologically safe until the very last moment the product is served.The neutralizing system suppresses the acidity and sourness of thepreservative system when the product is heated just before the productis served. Such a method avoids the need for thermalizing the foodproducts in advance, avoids overdrying of the food and requires lessenergy consumption.

EXAMPLES

[0066] The following examples are given by way of illustration of thepresent inventions and should in no way be considered as a limitation tothe system of the invention.

[0067] Using cold reconstituted mashed potatoes, the results suggestthat the neutralization system can resist the effects of abused storagetemperatures and provide a level of safety against bacterial growth.Furthermore, samples treated with various levels of theacid/neutralization system of the invention was able to extend longershelf-life than untreated samples under normal storage conditions.

Example 1

[0068] Experiments were carried out to confirm the effect of thepreservative, acidulant and neutralizing agent on the extension ofshelf-stability and robustness of the food composition.

[0069] An “in-house” mixture of bacteria derived from a water source wasgrown in Brain Heart Infusion broth (BHI; Difco, Detroit, Mich.) at 30°C. overnight (about 8 Hours). To acclimatize the microorganisms, theculture was divided into two equal portions and stored at either 6° C.or 12° C. for 8 Hrs.

[0070] “Maggi Mousline Purée de Pommes de Terre Flocons” (distributed byNestle FoodServices, France) was used in this study. Four types offormulations were evaluated. First, a control (about 500 g) was madeaccording to the manufacturer's instructions (i.e., without salt).Second, a series of reformulated mashed potato product were made (about500 g) with materials depicted in Table 1. The dry ingredients werethoroughly mixed prior to reconstitution with water. TABLE 1 List ofmaterials used to implement the acid/neutralization system of theinvention in mashed potatoes (% w/w) Ingredients Formula #1 Formula #2Formula #3 Potato flakes 14.300 14.300 14.300 (Mousline; Nestlé FoodService) Sodium Acetate 0.125 0.100 0.075 (Sigma; St. Louis, MO) CitricAcid 0.190 0.165 0.125 (Sigma; St. Louis, MO) Encapsulated Trisodium0.690 0.690 0.675 Phosphate at 30% activity (Balchem, State Hill, NY)Water 84.695 84.745 84.825 (Poland Spring water)*

[0071] The trisodium phosphate was granulates of 2% maximum on #10 meshand was encapsulated by partially hydrogenated vegetable oil. Theactivity of the phosphate (30%) corresponds to the amount that is notencapsulated. The It was manufactured by Balchem, State Hill, Mo.

[0072] Then, each reconstituted mashed potato product was divided intotwo equal halves. Each half of product was inoculated to achieve a finalconcentration of about 1×10³ colony forming units/g (cfu/g) with a mixedculture acclimatized to either 6 or 12° C. Depending on the type ofinoculum, the mashed potatoes were stored at 6 or 12° C. The experimentwas repeated. twice.

[0073] For all samples stored at 6 and 12° C., microbial analysis and pHdetermination were performed at day 0 and every second day.Determination of acidity of the mashed potato was performed byaseptically sampling product with a pH meter (Orion Model 420A). Sampleswere prepared for microbial analysis by performing a 1:10 dilution ofmashed potatoes in 0.1% peptone water (Difco, Detroit, Mich.) andstomached (seward Laboratory Blender, Model Stomacher 400; London, UK)for 2 min under the Normal Setting. Microbial analysis included spreadplates with aerobic plate count agar (Difco). Plates were incubated at30° C. for 24-48 Hrs and counted. Microbial analysis was performed induplicate for each sample.

[0074] All microbiological results were analyzed using the GeneralLinear Model of SAS (Statistical Analysis Software, Cary, N.C.).

[0075] Using the formulation depicted in table 1, products were preparedusing cold spring water and were refrigerated until the test day. Attesting, samples were heated to 82° C. using steam oven (RationalOriginal Combi-Steamer CCM 101; steam setting). The products were placedinto a steam table and held at 80° C. until presented to the panelists.

[0076] Under storage at 6° C., the initial pH of mashed potato withcontrol, formula #1, formula #2 and formula #3 were 6.05, 5.03, 4.97 and5.15, respectively. The results are visible in FIG. 1. The encapsulatedtrisodium phosphate in the treated samples slightly released during thestudy and raised the pH towards neutrality. The level where the pH hadincreased in the treated samples was dependent on the formulation of themashed potato product.

[0077] Upon examination of the aerobic plate count data, bacterialdevelopment occured after the 2^(nd) day in control samples. However,bacterial growth was considerably lower in all of the treated mashedpotatoes as it is shown in FIG. 2. Only, formulation #3 had a slightincrease in bacterial growth after 4^(th) day.

[0078] As shown in FIG. 3, similar findings were observed for samplesstored under 12° C. (i.e., abuse conditions). The initial pH of control,formula #1, formula #2 and formula #3 mashed potatoes were 6.01, 4.99,5.04 and 5.11, respectively. Once again, the encapsulated trisodiumphosphate slightly released and raised the treated samples towardsneutrality.

[0079] Under 12° C. storage, aerobic bacteria development steadilyincreased in control samples from day 0. In formulation #3 mashedpotatoes, bacterial development was significantly (p<0.001) suppressedfor 2 days. Then, bacterial development was initiated and reached 1×10⁶cfu/g by the 4^(th) day. A similar lag time was observed with theformula #2 mashed potatoes. However, bacterial development did not reach1×10⁶ cfu/g until the 6^(th) day. In formula #3 mashed potatoes, the lagtime was extend to 4 days and bacterial development never reached 1×10⁶chug even after 8 days of storage at 12° C. Those results areillustrated in FIG. 4.

[0080] At either storage conditions, bacterial growth appeared to besuppressed in all of the treated mashed potatoes until the pH reached5.8 to 6. Two possible explanations could be accounted for thisobservation. First, the reduction of antimicrobial activity would occuras the system increases in pH and subsequently, decreases the amount ofundissociated acid. Secondly, the bacterial population could compensatefor the preservation system at more neutral environments.

[0081] Using descriptive analysis, sensory evaluation was performed onthe various formulations of mashed potato product by 11 trainedpanelists. Samples were presented individually to the panelists in 4 ozplastic cups with lids and at a serving temperature of 71 ° C. Thepanelists were requested to evaluate different attributes of the productusing a 15 cm line scale. The attributes evaluated were: potato aroma,acidic aroma, potato flavor and sourness.

[0082] Analysis of variance and Duncan multiple range test was used tointerpret the results of the sensory evaluation.

[0083] At the time of sensory evaluation, all mashed potato products hadreached a pH of 6 to 6.2 upon heating. Of the three formulationevaluated, formula #3 was closest to the control mashed potatoes. Uponcooking (i.e., to 80° C. in a steam oven), the trained taste panelistswere unable to significantly (p>0.05) distinguish sour note betweencontrol samples and neutralized system of formula #3. However, it hadslightly lower levels of potato flavor.

[0084] In formulation #2 and #3, trained taste panelists were able tosignificantly (p<0.05) differentiate potato aroma, acidic aroma, potatoflavor when compared to control samples of mashed potato. All thoseresults are compiled in FIG. 5.

Example 2

[0085] In a seperate study, Listeria monocytogens (a foodborne pathogen)was inoculated into a mashed potato product with the acid/neutralizationsystem. The cold reconstituted mashed potatoes (Mousline) was made upwith and without 0.125% acetate and encapsulated tri-sodium phosphate(Formula #1). Listeria monocytogenes was added to both the control (noacid/phosphate) and treated samples at 100 cfu/g. These samples werethen incubated at 6° C. and analyzed every two days for up to 8 days forthe growth of Listeria monocytogenes.

[0086] In Table 2, the results show that Listeria monocytogenes wascontrolled by the acid/neutralization system over a period of 8 days.

[0087] Table 2: Growth of Listeria monocytogenes in mashed potatoestreated with and without the acid and neutralization system of theinvention Control (Listeria Test (Listeria counts Days at 6° C. countslog cfu/g) log cfu/g) 0 1.5 1.5 2 1.8 1.5 4 3.0 1.6 6 3.8 1.6 8 4.9 1.7

[0088] Although the present invention has been described in terms ofpreferred embodiments, it will be appreciated that many alterations andmodifications of the invention will no doubt become apparent to those ofordinary skill in the art. Accordingly, it is intended that thedisclosure be considered as exemplary rather than limiting, and that theappended claims be interpreted as covering all such alterations andmodifications that fall within the true spirit and scope of theinvention.

What is claimed is:
 1. A food composition comprising an acidifyingpreservative system adapted to reduce the microbial growth in thecomposition when the composition is stored in microbiologicallysensitive conditions, the composition including a neutralizing systemwhich is inactivated in the microbiologically sensitive conditions butis adapted to activate on demand upon reactivating conditions of theneutralizing system so that the neutralizing system acts on theacidifying preservative system to reduce its sourness and/or aciditythereby improving the taste perception of the food composition.
 2. Afood composition according to claim 1, wherein the neutralizing systemis reactivable by heating the composition.
 3. A food compositionaccording to claim 2, wherein the neutralizing system is encapsulated tosubstantially resist, or at least delay, release of the neutralizingeffect when the composition is maintained in the microbiologicallysensitive conditions of storage.
 4. A food composition according toclaim 1, wherein the microbiologically sensitive conditions of storageessentially consists in maintaining the food composition in hydratedform under chilled temperatures.
 5. A food composition according toclaim 1, wherein the acidifying preservative system comprises at leastone organic acid associated to a salt of organic acid wherein the saltof organic acid is adapted to dissociate in aqueous state to form withthe organic acid an effective antimicrobial effect.
 6. A foodcomposition according to claim 5, wherein the organic acid is citricacid, ascorbic acid, sorbic acid, tartaric acid, cream of tarter,fumaric acid, lactic acid, malic acid, acetic acid, and combinationsthereof.
 7. A food composition according to claim 5, wherein the salt oforganic acid is sodium acetate, monosodium citrate, trisodium citrate,potassium benzoate, sodium benzoate, potassium citrate, potassiumgluconate, potassium sorbate, and combination thereof.
 8. A foodcomposition according to claim 5, wherein the acidulent and thesalt-based preservative agent are used in combination at a ratio of from1:1 to 5:1 (wt/wt).
 9. A food composition according to claim 5, whereinthe neutralizing system comprises a pH raising agent selected from thegroup consisting of organic phosphates, oxides, hydroxides orcombinations thereof.
 10. A food composition according to claim 9,wherein the pH raising agent is selected from the group consisting ofmono-sodium phosphate, di-sodium phosphate, tri-sodium phosphate,calcium phosphate, sodium bicarbonate, calcium oxide, calcium hydroxide,sodium hydroxide and combinations thereof.
 11. A food compositionaccording to claim 9, comprising between about 0.05 to 5 % wt of theorganic acid, between about 0.05 to 5 % wt of the salt of the organicacid and between about 0.05 to 8 % wt of the pH raising agent.
 12. Afood composition according to claim 11, comprising between about 0.1 to2 % wt of the organic acid, between 0.1 to 2 % wt of the salt of theorganic acid and between about 1 to 6 % wt of a pH raiser.
 13. A foodcomposition according to claim 11, comprising from about 0.1 to 2 wt %citric acid, from about 0.1 to 2 wt % sodium acetate and from 1 to 6 wt% encapsulated trisodium phosphate.
 14. A food composition according toclaim 1, in dehydrated form and capable of reconstitution by contactwith an aqueous medium.
 15. A food composition according to claim 14,wherein the food is a naturally low acid food.
 16. A food compositionaccording to claim 15, wherein the food comprises mashed vegetables. 17.A food composition according to claim 15, wherein the food comprisesingredients for reconstituting a sauce or soup.
 18. A food compositionaccording to claim 1, wherein the food is at least a partially hydratedfood.
 19. A food composition according to claim 18, wherein the food isa concentrate.
 20. A food composition according to claim 18, wherein thefood is a fully hydrated food.
 21. A food composition according to claim1, wherein said preservative system is effective to preserve thecomposition against microbial spoilage during at least 2 days at chilledstorage conditions.
 22. A method for increasing both shelf stability ofa food composition under standard storage temperature conditions androbustness of the composition under abuse storage temperature conditionsby adding to the food composition an acidifying preservative system insufficient amounts to reduce microbial spoilage in the food, and anon-demand reactivable neutralizing system which is inactivated understandard storage conditions but is adapted to activate on demand uponreactivating conditions of the neutralizing system so that theneutralizing system acts on the acidifying preservative system todecrease the sourness and/or acidity of the food when the neutralizingsystem is activated.
 23. A method according to claim 22, wherein thefood composition is hydrated before storage.
 24. A method according toclaim 22, wherein the neutralizing system is activable by heating thefood composition.
 25. A method according to claim 22, wherein the foodcomposition comes from a dehydrated composition that is moisturized forstoring in refrigerated conditions.
 26. A method according to claim 23,wherein the heat-activable neutralizing system is present in themoisturized composition in an encapsulated form.
 27. A method accordingto claim 25, wherein the heat-activable neutralizing system is presentin the dehydrated composition in an encapsulated form.
 28. A methodaccording to claim 22, wherein the heat-activable neutralizing system isadded separately at the time the composition is moisturized.
 29. Amethod for providing to a foodservice, manufacturing or selling locationa hydrated food composition having improved microbiological robustnesswhich comprises providing a dehydratable food composition including adry food component, a preservative system effective to reducemicrobiological growth during refrigerated or abuse conditions, and aneutralizing system that is essentially activable when the foodcomposition is substantially heated, such that the neutralizing system,when activated, acts to increase the organoleptic properties of the foodproduct.
 30. A dry blend of an acidifying preservative system adapted toprevent or at least reduce the microbial growth of a food when the foodis stored in microbiologically sensitive conditions and a neutralizingsystem, wherein the neutralizing system is encapsulated to substantiallydelay its release during storage at the microbiologically sensitiveconditions, but is adapted to fully release upon heating of theneutralizing system so that the neutralizing system acts on theacidifying preservative system to neutralize its sourness and/or aciditythereby improving the taste perception of the food.
 31. Dry blendaccording to claim 30, wherein the acidifying preservative systemcomprises at least one organic acid associated to a salt of organic acidin a ratio of from 1:1 to 5:1.
 32. Dry blend according to claim 31,wherein the neutralizing system comprises a pH raiser agent selectedamong the family of organic phosphate, oxyde, hydroxyde or combinationsthereof and is encapsulated in water-resistant, heat-sensitive, fatbased encapsulation.
 33. Dry blend according to claim 32, wherein the pHraiser agent is encapsulated with a water resistant, heat melting fatbased coating.
 34. Dry blend according to claim 34, wherein the fatbased coating comprises vegetable oil.
 35. Dry blend according to claim31, wherein the acidifying system and neutralizing system is present ina ratio of from 1:1 to 1:10.
 36. A method for improving taste perceptionor organoleptic properties of a food composition which comprisesincorporating in the food composition a combination of an acidifyingpreservative system and a neutralizing system, wherein said acidifyingpreservative system is effective for reducing the microbial growth inthe food composition and the neutralizing system is inactivated duringstorage of the food compsosition at microbiologically sensitiveconditions, but is adapted to activate on demand to act on theacidifying preservative system to neutralize its sourness and/or aciditythereby improving the taste perception or organoleptic of the foodcomposition.